Describe what happens when you jump from a small boat onto a dock from the perspective of the 3rd law.

according to newton's third law, every action has equal and opposite reaction. in this scenario of making a jump from the boat onto a dock, as i jump my feet in contact with the boat push the boat in backward direction. hence the action force is the push by my feet on the boat. the boat reacts by applying a reaction force on my feet pushing the feet in forward direction. hence reaction force here is the force by the boat on the feet. due to the reaction force of the boat on feet, i am pushed in forward direction to reach the the dock.

i would say

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y